This investigation is concerned with three aspects of cell pH. First, the effect of potassium and chloride depletion on cell pH and renal citrate and ammonia metabolism will be examined. In this portion of the study rats will be both potassium and chloride depleted and the effect of repleting either or both of these ions on renal citrate content and urinary citrate and ammonia excretion measured. It appears that citrate metabolism in potassium deficiency is regulated by cell pH so changes in renal citrate metabolism should reflect changes in renal tubular cell pH. The comparative roles of chloride and extracellular volume in potassium deficiency will also be studied. The second aspect of cell pH to be investigated relates to the possible role of anaerobic glycolysis in regulating cell pH. The specific glucose competitive inhibitor, 2 deoxy-glucose, will be infused into rats and its effect on whole body, heart, skeletal muscle, and liver pH measured using a DMO triple isotope method. In addition, effects on renal cell pH will be investigated by examining renal citrate excretion and content. Experiments will be performed under physiologic extracellular A-B conditions as well as in metabolic and respiratory acidosis and alkalosis. The third aspect of the study concerns the possible role of the parathyroids in the disposition of acute acid loads. The postulate is that a large portion of acutely administered acid is buffered by bone and this buffering is related/to parathyroid activity. Acid will be administered intravenously to nephrectomized rats and the distribution of acid between extracellular and intracellular compartments compared in parathyroidectomized & non- parathyroidectomized rats. In addition, whole body pH, heart, liver, and muscle cell pH will be calculated using the triple isotope technique.